The efficiency of tumble finishing as a final post-treatment for fatigue enhancement of notched laser powder bed fusion AlSi10Mg

: A hybrid post-treatment combining tumble finishing as a final step after shot peening and heat treatment was developed to alleviate the adverse effects of internal and surface defects on the fatigue performance of laser powder bed fusion AlSi10Mg samples. The effects of each post-treatment were investigated individually and synergistically on microstructure, surface morphology and roughness, hardness, residual stresses, porosity, and rotating bending fatigue behavior of V-notched AlSi10Mg samples. The results reveal that tumble finishing can highly reduce surface roughness by 28 and 32% compared to the as-built and heat-treated states while inducing extra surface layer hardening and compressive residual stresses. The hybrid post-treatment of heat treatment + shot peening + tumble finishing significantly increased the fatigue life of the samples by over 500 times higher compared to the as-built series

Alternative Oxidase (AOX) Senses Stress Levels to Coordinate Auxin-Induced Reprogramming From Seed Germination to Somatic Embryogenesis—A Role Relevant for Seed Vigor Prediction and Plant Robustness

Somatic embryogenesis (SE) is the most striking and prominent example of plant plasticity upon severe stress. Inducing immature carrot seeds perform SE as substitute to germination by auxin treatment can be seen as switch between stress levels associated to morphophysiological plasticity. This experimental system is highly powerful to explore stress response factors that mediate the metabolic switch between cell and tissue identities. Developmental plasticity per se is an emerging trait for in vitro systems and crop improvement. It is supposed to underlie multi-stress tolerance. High plasticity can protect plants throughout life cycles against variable abiotic and biotic conditions. We provide proof of concepts for the existing hypothesis that alternative oxidase (AOX) can be relevant for developmental plasticity and be associated to yield stability. Our perspective on AOX as relevant coordinator of cell reprogramming is supported by real-time polymerase chain reaction (PCR) analyses and gross metabolism data from calorespirometry complemented by SHAM-inhibitor studies on primed, elevated partial pressure of oxygen (EPPO)–stressed, and endophyte-treated seeds. In silico studies on public experimental data from diverse species strengthen generality of our insights. Finally, we highlight readyto- use concepts for plant selection and optimizing in vivo and in vitro propagation that do not require further details on molecular physiology and metabolism. This is demonstrated by applying our research & technology concepts to pea genotypes with differential yield performance in multilocation fields and chickpea types known for differential robustness in the field. By using these concepts and tools appropriately, also other marker candidates than AOX and complex genomics data can be efficiently validated for prebreeding and seed vigor prediction

Alternative Oxidase (AOX) Senses Stress Levels to Coordinate Auxin-Induced Reprogramming From Seed Germination to Somatic Embryogenesis—A Role Relevant for Seed Vigor Prediction and Plant Robustness

Somatic embryogenesis (SE) is the most striking and prominent example of plant plasticity upon severe stress. Inducing immature carrot seeds perform SE as substitute to germination by auxin treatment can be seen as switch between stress levels associated to morphophysiological plasticity. This experimental system is highly powerful to explore stress response factors that mediate the metabolic switch between cell and tissue identities. Developmental plasticity per se is an emerging trait for in vitro systems and crop improvement. It is supposed to underlie multi-stress tolerance. High plasticity can protect plants throughout life cycles against variable abiotic and biotic conditions. We provide proof of concepts for the existing hypothesis that alternative oxidase (AOX) can be relevant for developmental plasticity and be associated to yield stability. Our perspective on AOX as relevant coordinator of cell reprogramming is supported by real-time polymerase chain reaction (PCR) analyses and gross metabolism data from calorespirometry complemented by SHAM-inhibitor studies on primed, elevated partial pressure of oxygen (EPPO)–stressed, and endophyte-treated seeds. In silico studies on public experimental data from diverse species strengthen generality of our insights. Finally, we highlight ready-to-use concepts for plant selection and optimizing in vivo and in vitro propagation that do not require further details on molecular physiology and metabolism. This is demonstrated by applying our research & technology concepts to pea genotypes with differential yield performance in multilocation fields and chickpea types known for differential robustness in the field. By using these concepts and tools appropriately, also other marker candidates than AOX and complex genomics data can be efficiently validated for prebreeding and seed vigor prediction.</p

Paper as a Simple Tool to Study Bacterial Ecology

Community interactions based on various parameters in defined niches have been studied to understand their influence on bacterial life. Yet there currently are no models that can depict how spatial interactions control the complex combinatorics of different microbial communities. Biodiversity influences the ecosystem properties of bacterial communities, but the relationship between bacterial biodiversity and function remains to be understood entirely. Here, the focus is on developing a simple and effective platform to study neighborhood interactions between different species of lactic acid bacteria by controlling two metrics – distance and composition. Using this simple platform, I explore 1) how spatial and temporal arrangement between different bacteria affect their interaction in a high throughput manner, 2) how biodiversity can be manipulated in terms of its starting population, the number of species, and species identity

MALDI-HRMS Imaging Maps the Localization of Skyrin, the Precursor of Hypericin, and Pathway Intermediates in Leaves of Hypericum Species

Hypericum perforatum and related species (Hypericaceae) are a reservoir of pharmacologically important secondary metabolites, including the well-known naphthodianthrone hypericin. However, the exact biosynthetic steps in the hypericin biosynthetic pathway, vis-&agrave;-vis the essential precursors and their localization in plants, remain unestablished. Recently, we proposed a novel biosynthetic pathway of hypericin, not through emodin and emodin anthrone, but skyrin. However, the localization of skyrin and its precursors in Hypericum plants, as well as the correlation between their spatial distribution with the hypericin pathway intermediates and the produced naphthodianthrones, are not known. Herein, we report the spatial distribution of skyrin and its precursors in leaves of five in vitro cultivated Hypericum plant species concomitant to hypericin, its analogs, as well as its previously proposed precursors emodin and emodin anthrone, using MALDI-HRMS imaging. Firstly, we employed HPLC-HRMS to confirm the presence of skyrin in all analyzed species, namely H. humifusum, H. bupleuroides, H. annulatum, H. tetrapterum, and H. rumeliacum. Thereafter, MALDI-HRMS imaging of the skyrin-containing leaves revealed a species-specific distribution and localization pattern of skyrin. Skyrin is localized in the dark glands in H. humifusum and H. tetrapterum leaves together with hypericin but remains scattered throughout the leaves in H. annulatum, H. bupleuroides, and H. rumeliacum. The distribution and localization of related compounds were also mapped and are discussed concomitant to the incidence of skyrin. Taken together, our study establishes and correlates for the first time, the high spatial distribution of skyrin and its precursors, as well as of hypericin, its analogs, and previously proposed precursors emodin and emodin anthrone in the leaves of Hypericum plants

Developing a best practice for sample preparation of additive manufactured AlSi10Mg for electron backscatter diffraction analysis

Microstructural characterization has a key role in analyzing the properties of additive manufactured materials. Electron backscatter diffraction (EBSD) can offer a unique set of information on the microstructural state of these materials. However, EBSD analyses is extremely sensitive to the quality of the prepared sample and requires a seamless preparation eliminating any risk of contamination, oxidation or surface imperfections. Despite the wide use of EBSD analysis in AM, there is no universally accepted sample preparation protocol and the variety and sequence of the steps that can guarantee high quality data remain unclear. In this study, the efficiency of sample preparation methods with various final steps of vibrational polishing, vibrational polishing + cleaning, vibrational polishing + electro-chemical polishing and vibrational polishing + chemical etching was surveyed and compared for EBSD analyses of notched AM AlSi10Mg part. The obtained results help selecting the most efficient approach indicating that vibrational polishing + chemical etching with hit rate of 95.41% lead to the lowest zero solutions followed by vibrational polishing + electro-chemical polishing, vibrational polishing + pad cleaning and just vibrational polishing, respectively

An Implementation Study of a Dynamic Inter-Domain Bandwidth Management Platform in Diffserv Networks

In this paper, we assess the scalability and efficiency of a scalable Bandwidth Management Point (BMP) for guaranteed Quality-of-Service in Diffserv networks. Our BMP uses centralized network state maintenance and pipe-based intra-domain resource management schemes that significantly reduce the admission control time and minimize the scalability problems present in prior research. We have designed, developed and implemented an enhanced Simple Inter-Domain Bandwidth Broker Signaling (SIBBS) protocol for interdomain communication. The BMP uses dynamic inter-domain pipes to handle inter-domain provisioning and dynamic provisioning schemes to increase signaling scalability. To assess our BMP implementation in terms of signaling scalability and effective resource utilization, Preprint submitted to noms 9 August 2003 we conducted experiments on a test-bed demonstrating how a BMP substantially increases resource utilization and scalability while requiring minimum changes in the underlying infrastructure

Transformations of lignans, part V. Reactions of DDQ with a gmelinol hydrogenolysis product and its derivatives

Hydrogenolysis of gmelinol 8 with sodium in liquid ammonia gives a triol 9, which is converted under various reaction conditions into a range of derivatives including the di- and tri-O-methyl ethers 10 and 11, a 3,4-dibenzyl-3-hydroxy-tetrahydrofuran 12, and its acetate 13. These derivatives undergo oxidative cyclisation with DDQ in acetic acid or trifluoroacetic acid to yield 1-aryltetralin, 1-arylnaphthalene, dibenzocyclooctadiene and spirodienone derivatives in reactions which provide biomimetic analogies for biogenetic transformations of lignans